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Ferrimagnetic insulators (FMIs) have abundant advantages for the application in spintronic devices, which have attracted intensive studies. However, in most previous studies on heavy metal (HM)/FMI bilayers, the FMI layers are deposited by pulsed laser deposition (PLD), and the HM layers are deposited by magnetron sputtering. This will cause the interfacial contamination due to the inevitable vacuum breaking, and then significantly affect the spin‐orbit torque (SOT) generation and the Dzyaloshinskii–Moriya interaction (DMI) in the HM/FMI bilayers. In this work, the SOT and DMI in the HM/FMI bilayers deposited by magnetron sputtering without vacuum breaking are studied. The successful fabrication of the Tm3Fe5O12 (TmIG) layer, a typical FMI, with good crystallinity and perpendicular magnetic anisotropy (PMA) by magnetron sputtering is first demonstrated. Then by systematically varying the TmIG thickness, the SOT and DMI in the Pt/TmIG bilayers are studied. It is shown that the effective spin Hall angle in the Pt/TmIG bilayers is much larger than most previously reported values. It is further demonstrated that the DMI constant scales linearly with the inverse of the TmIG thickness, indicating the interfacial origin of the DMI. The study provides a piece of information for the basic understandings of the SOT and DMI in the HM/FMI bilayers. [ABSTRACT FROM AUTHOR]

Self‐assembled monolayers (SAMs) have significantly improved the device performance of inverted perovskite solar cells (PSCs). However, the inadequate chemical bonding affinity between SAMs and the substrate as well as the uneven SAM distribution can lead to the decrease in device performance. Herein, the study reports a bilayer NiOx hole transport layer (HTL), consisting of ultrathin NiOx buffer film prepared through atomic layer deposition (ALD‐NiOx) and spin‐coated NiOx film (Spin‐NiOx). The work function difference between the two NiOx films will facilitate the hole transfer from the ALD‐NiOx to the Spin‐NiOx in the ALD‐NiOx/Spin‐NiOx bilayer structure. These holes will undergo surface hydroxylation reactions with water molecules on the Spin‐NiOx film surface, generating additional hydroxyl groups covalently bonded to the Spin‐NiOx film, which can provide more anchoring sites for SAM molecules. Stable covalent bonds can be formed between the Spin‐NiOx film and the subsequently coated SAM film. As a result, SAM films with better coverage and molecular arrangement can be obtained. The ALD‐NiOx/Spin‐NiOx/SAM composite HTL also demonstrates superior charge transport capability and thermal stability. For small area PSCs (0.06 cm2) prepared by using the composite HTL, a champion power conversion efficiency (PCE) of 25.25% is achieved, and the device stabilities are also significantly improved. [ABSTRACT FROM AUTHOR]

In this work we present self-organized regular patterns in a solution system through uphill-diffusion. Micrometer thick organic semiconductor solution is sandwiched between a substrate and cover-plate. Self-assembled regular patterns can be observed on the substrate after solvent evaporation. Different micro-patterns and pattern defects were displayed and analyzed. Mechanisms of defect formation, mode selection process during patten generation, and pattern sedimentation onto substrate from solution were proposed. Organic thin film transistors were fabricated with the assembled line patterns which demonstrate a promising way to produce patterned micro/nano materials., (© 2024 IOP Publishing Ltd. All rights, including for text and data mining, AI training, and similar technologies, are reserved.)

Water processing is an ideal strategy for the ecofriendly fabrication of organic photovoltaics (OPVs) and exhibits a strong market-driven demand. Here, we report a state-of-the-art active material, namely PM6:BTP-eC9, for the synthesis of water-borne nanoparticle (NP) dispersion towards ecofriendly OPV fabrication. The surfactant-stripping technique, combined with a poloxamer, facilitates purification and eliminates excess surfactant in water-dispersed organic semiconducting NPs. The introduction of 1,8-diiodooctane (DIO) for the synthesis of surfactant-stripped NP (ssNP) further promotes a percolated microstructure of the polymer and NFA in each ssNP, yielding water-processed OPVs with a record efficiency of over 11%. The use of an additive during water-borne ssNP synthesis is a promising strategy for morphology optimization in NP OPVs. It is believed that the findings in this work will engender more research interest and effort relating to water-processing in preparation of the industrial production of OPVs.

Inverse photoresponse is discovered from phototransistors based on molybdenum disulfide (MoS 2 ). The devices are capable of detecting photons with energy below the bandgap of MoS 2 . Under the illumination of near-infrared (NIR) light at 980 and 1550 nm, negative photoresponses with short response time (50 ms) are observed for the first time. Upon visible-light illumination, the phototransistors exhibit positive photoresponse with ultrahigh responsivity on the order of 10 4 -10 5 A W -1 owing to the photogating effect and charge trapping mechanism. Besides, the phototransistors can detect a weak visible-light signal with effective optical power as low as 17 picowatts (pW). A thermally induced photoresponse mechanism, the bolometric effect, is proposed as the cause of the negative photocurrent in the NIR regime. The thermal energy of the NIR radiation is transferred to the MoS 2 crystal lattice, inducing lattice heating and resistance increase. This model is experimentally confirmed by low-temperature electrical measurements. The bolometric coefficient calculated from the measured transport current change with temperature is -33 nA K -1 . These findings offer a new approach to develop sub-bandgap photodetectors and other novel optoelectronic devices based on 2D layered materials., (© 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

Electronics based on solution-processable materials are promising for applications in many fields which stimulated enormous research interest in liquid-drying and pattern formation. However, assembling of structure with submicrometre/nanometre resolution through liquid process is very challenging. We show a simple method to rapidly generate polymer structures with deep-submicrometre-sized features over large areas. In this method, a solution film is dried on a substrate under a suspended flexible template with groove/ridge surface topography. Upon solvent evaporation, the solution splits in the grooves and forms capillary bridges between the template and substrate, which are firmly pinned by the edges of the template grooves. This groove pinning stabilizes the contact lines, thereby allowing the formation of fine patterned structures with high aspect ratios which were used to fabricate various functional materials and electronic devices. We also produced secondary self-assembled nano-stripe patterns with resolutions of about 50 nm on the primary lines.